CN112889012B - Control system - Google Patents
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- CN112889012B CN112889012B CN201980069744.XA CN201980069744A CN112889012B CN 112889012 B CN112889012 B CN 112889012B CN 201980069744 A CN201980069744 A CN 201980069744A CN 112889012 B CN112889012 B CN 112889012B
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- 238000001514 detection method Methods 0.000 claims abstract description 150
- 230000000630 rising effect Effects 0.000 claims abstract description 65
- 238000012544 monitoring process Methods 0.000 claims abstract description 63
- 230000004044 response Effects 0.000 claims abstract description 11
- 238000005520 cutting process Methods 0.000 claims description 35
- 230000033001 locomotion Effects 0.000 claims description 22
- 230000005540 biological transmission Effects 0.000 claims description 9
- 238000000034 method Methods 0.000 description 32
- 101100203598 Plasmodium falciparum (isolate NF54) SOPT gene Proteins 0.000 description 25
- 230000008569 process Effects 0.000 description 25
- 238000012545 processing Methods 0.000 description 14
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- 230000001174 ascending effect Effects 0.000 description 5
- 238000013459 approach Methods 0.000 description 4
- 230000008859 change Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 238000000926 separation method Methods 0.000 description 4
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- 238000013461 design Methods 0.000 description 2
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D3/00—Control of position or direction
- G05D3/12—Control of position or direction using feedback
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B19/00—Programme-control systems
- G05B19/02—Programme-control systems electric
- G05B19/04—Programme control other than numerical control, i.e. in sequence controllers or logic controllers
- G05B19/042—Programme control other than numerical control, i.e. in sequence controllers or logic controllers using digital processors
- G05B19/0426—Programming the control sequence
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Abstract
A control system that monitors a control state of a target device that is driven and controlled by a motor, the control system comprising: a setting unit that sets an origin for position monitoring for a target device; and a sensor that detects that the target device has reached a predetermined position. The setting unit further includes: an acquisition unit that acquires the rise and fall of a detection signal output from a sensor in response to the target device reaching a predetermined position when the target device is subjected to predetermined drive control by a motor; and a calculation unit that calculates an origin using the 1 st position information related to the position of the target device calculated from the rising and falling of the detection signal and the 2 nd position information related to the position of the target device, the 2 nd position information being different from the 1 st position information. According to this configuration, the safety performance relating to the position monitoring of the target device controlled by the motor drive can be improved more simply.
Description
Technical Field
The present invention relates to a control system for monitoring a control state of a target device that is driven and controlled by a motor.
Background
An origin sensor for determining an approximate origin on a straight line for moving a table or the like is disposed for aligning the origin of a linear motion device for accurately moving the table or the like to a predetermined position, and the origin position is determined from an output signal of the sensor and a rotational origin signal of an incremental encoder attached to a motor. However, in such origin point alignment, the position adjustment of the point sensor and the encoder angle adjustment are repeated a plurality of times by turning on and off the power supply of the motor, and therefore, a high degree of skill and a great deal of man-hours are required. For this reason, for example, in the technique disclosed in patent document 1, the position of the table origin sensor is detected, and whether or not the position is appropriate is checked, and then the motor is manually turned off, so that the position of the table origin sensor is moved to set the origin while observing a rotation cycle signal accompanying the rotation of the motor.
Prior art literature
Patent literature
Patent document 1: japanese patent laid-open No. 10-6179
Disclosure of Invention
Problems to be solved by the invention
Conventionally, in order to improve safety performance when monitoring a position of a target device, which is one of control states of the target device, a redundant sensor, an encoder to which high safety performance is imparted, and the like have been used for setting an origin position for the position monitoring. In order to cope with such high security performance, in the design of an encoder, it is necessary to satisfy the condition of a prescribed security standard. For example, IEC61508 is defined as the security standard. IEC61508 is an international standard for electrical/electronic/programmable electronic security related functional security. In IEC61508, as shown in Table 1 below, the failure probability of a system is specified in a scale called SIL (SAFETY INTEGRITY LEVEL: safety integrity level).
TABLE 1
Moreover, in IEC61508, each SIL in the table defines the requirements that should be met, defining the measures that the system to be built should achieve. The greater the value of SIL, which is divided into 4 phases SIL1 to SIL4, the higher the safety performance. In addition, in order to increase the value of the SIL, the position of the target device needs to be monitored, and the SIL of the encoder to be used needs to be increased, which may increase the cost of the device or complicate the design of the device.
The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a technique capable of improving safety performance related to position monitoring of a target device that is driven and controlled by a motor with a simpler structure.
Means for solving the problems
In order to solve the above problems, the present invention calculates 1 st position information related to the position of the target device using both the rising and falling of the detection signal outputted from the position sensor of the target device, and further uses 2 nd position information different from the 1 st position information, whereby the safety performance related to the position monitoring of the target device can be improved.
Specifically, the present invention is a control system for monitoring a control state of a target device controlled by motor driving, the control system including: a determination unit that calculates a position of the target device based on a signal from an encoder included in the motor, and determines whether the position of the target device falls within a predetermined monitoring range; a cutting unit that cuts off transmission of a drive signal transmitted to the drive unit in order to supply a drive current from the drive unit to the motor; a safety control unit that executes a cutting process of the drive signal via the cutting unit when the determination unit determines that the position of the target device does not belong to the predetermined monitoring range; a setting unit that sets an origin for the predetermined monitoring range; and at least one sensor for detecting the arrival when the target device reaches a predetermined position by driving the target device by the motor within a movable range of the target device. The setting unit further includes: an acquisition unit that acquires, with respect to a detection signal output from the at least one sensor in response to the target device reaching the predetermined position when the motor performs predetermined drive control on the target device, an ascent of the detection signal in response to the target device approaching the predetermined position and a descent of the detection signal in response to the target device being separated from the predetermined position; and a calculation unit that calculates the origin using 1 st position information related to the position of the target device calculated from the rising and falling of the detection signal and 2 nd position information related to the position of the target device, the 2 nd position information being different from the 1 st position information.
The control system of the present invention is a device for monitoring a control state of a target device, particularly a state of a position thereof, which is driven and controlled by a motor. The control system may be integrated with a servo driver, an inverter, or the like, which is a device for driving the motor, or may be configured as a device separate from the devices for driving the motor. Further, an encoder is provided at the motor, and the control system of the present invention grasps the position of the target device from a feedback signal related to position information, speed information, and the like from the encoder, and monitors the position.
Here, the control system includes a cutting unit that cuts off transmission of the drive signal to a driving unit for supplying electric power to the motor. The drive signal is a signal for generating a drive current to be supplied from the drive unit to the motor to cause the target device to perform a predetermined operation, and is transmitted from a structural unit higher than the drive unit to the drive unit. Therefore, the cutting unit is configured to cut off transmission of the driving signal during transmission from the upper structural unit to the driving unit. When it is determined that the position of the target device does not belong to a predetermined monitoring range that should be safely present with respect to the driving of the motor, the safety control unit executes the process of cutting off the driving signal, thereby realizing the safety performance based on the control system.
In order to monitor the position of the target device by the control system, the following origin setting process is performed: a predetermined monitoring range based on the setting unit is appropriately determined. At least one sensor that emits a detection signal associated with the position of the target device is used in the setting process based on the origin of the setting section. When the target device reaches a predetermined position, the sensor generates an increase in the detection signal in response to the approach of the target device, and generates a decrease in the detection signal in response to the separation of the target device. The acquisition unit acquires the rising and falling of the detection signal in common. Then, the calculation unit calculates the 1 st position information based on the rise and fall of the acquired detection signal. Since the 1 st position information is calculated in consideration of both the rising and falling of the detection signal, it is possible to obtain information indicating the position of the target device, which is not easily affected by which direction the target device has reached the predetermined position. The calculation unit calculates the origin for position monitoring using the 1 st position information and the 2 nd position information. The 2 nd position information is information related to the position of the target device, but is information independent of the 1 st position information. Therefore, the calculation unit can set the origin by causing the 1 st position information and the 2 nd position information to interact with each other.
As described above, in the control system according to the present invention, the origin set by the setting unit is less susceptible to the movement of the object device for origin setting, and the positional accuracy is relatively high. This means that according to table 1 described above, even if the safety performance of the encoder is relatively low, the safety performance itself based on the control system can be improved. For example, the value of the SIL related to the safety performance of the control system can be increased over the value of the SIL related to the safety performance of the encoder. As a result, as a control system, safety performance relating to position monitoring of a target device controlled by motor driving can be improved with a simpler structure.
Here, in the control system, the at least one sensor may include a 1 st sensor that detects that the target device reaches a 1 st predetermined position, which is the predetermined position, and a 2 nd sensor that detects that the target device reaches a 2 nd predetermined position. In this case, the acquiring unit may acquire the rising and falling of the detection signal from the 1 st sensor and the rising and falling of the detection signal from the 2 nd sensor, and the calculating unit may calculate the 1 st position information based on the rising and falling of the detection signal from the 1 st sensor in accordance with the movement of the target device under the predetermined drive control, calculate the 2 nd position information based on the rising and falling of the detection signal from the 2 nd sensor, and calculate a predetermined candidate location between the position indicated by the 1 st position information and the position indicated by the 2 nd position information as the origin in accordance with the movement of the target device under the predetermined drive control.
In such a configuration, the setting unit sets the origin based on the 1 st position information associated with the 1 st predetermined position and the 2 nd position information associated with the 2 nd predetermined position. Both the 1 st position information and the 2 nd position information are calculated by using the rising and falling of each detection signal, and therefore, are not easily affected by the movement of the object device, and the position accuracy is relatively high. Therefore, the position accuracy of the predetermined candidate location as the origin calculated from the 1 st position information and the 2 nd position information can be relatively high. Further, regarding the predetermined candidate location, it is possible to determine between the position indicated by the 1 st position information and the position indicated by the 2 nd position information based on the movement of the target device in the predetermined drive control for detecting the arrival at each predetermined position by each sensor. For example, in the predetermined drive control, when the target device is driven at a constant speed, the calculation unit may calculate the 1 st position information from a middle point between the rising and falling of the detection signal from the 1 st sensor, calculate the 2 nd position information from a middle point between the rising and falling of the detection signal from the 2 nd sensor, and determine a position indicated by the 1 st position information and a position indicated by the 2 nd position information as the predetermined candidate location, or may determine a predetermined candidate location other than the predetermined candidate location.
Here, in the control system described above, two modes are exemplified as to the arrangement modes of the 1 st sensor and the 2 nd sensor. In the 1 st aspect, two sensors may be disposed so that the 1 st predetermined position is distant from the 2 nd predetermined position, and the on-time from the rising to the falling of the detection signal from the 1 st sensor may not overlap with the on-time from the rising to the falling of the detection signal from the 2 nd sensor. The degree of distance between the 1 st predetermined position and the 2 nd predetermined position can be determined in consideration of the structure, size, and the like of the target device. For example, the 1 st predetermined position and the 2 nd predetermined position may be positions indicating both ends of the movable range of the target device. In this case, a general limit switch or the like can be used as the 1 st sensor and the 2 nd sensor.
In the 2 nd aspect, two sensors may be arranged so that the 1 st predetermined position is close to or coincides with the 2 nd predetermined position, and a part or all of an on-time from the rising to the falling of the detection signal from the 1 st sensor may overlap with an on-time from the rising to the falling of the detection signal from the 2 nd sensor. In this case, the degree of distance between the 1 st predetermined position and the 2 nd predetermined position can be determined in consideration of the structure, size, and the like of the target device. For example, a general proximity sensor or the like can be used as the 1 st sensor and the 2 nd sensor.
Here, in the control system described above, the acquisition unit may be configured to: in the predetermined drive control, when the target device performs the turning-back operation in a period from the rise of the detection signal from the 1 st sensor to the passage of the 1 st predetermined position, the detection signal from the 1 st sensor may not be acquired, and the control unit may be configured to: in the predetermined drive control, when the target device performs the turning-back operation in a period from the rise of the detection signal from the 2 nd sensor to the passage of the 2 nd predetermined position, the rise and fall of the detection signal from the 2 nd sensor are not acquired. When such a folding operation is performed, the rising and falling of the detection signal to be originally acquired in each sensor are discontinuously outputted, and thus it becomes difficult to acquire position information that is not easily affected by the movement of the target device. Therefore, when the folding operation is performed, the process of the acquisition unit is preferably not performed.
In the control system described above, the setting unit may be configured such that the setting unit does not set the origin for the predetermined monitoring range when at least one of a1 st condition and a2 nd condition is not satisfied, the 1 st condition being that a1 st check distance calculated from an increase in the detection signal from the 1 st sensor and an increase in the detection signal from the 2 nd sensor is equal to or smaller than a predetermined 1 st reference distance, and the 2 nd condition being that a2 nd check distance calculated from a decrease in the detection signal from the 1 st sensor and a decrease in the detection signal from the 2 nd sensor is equal to or smaller than a predetermined 2 nd reference distance. By adopting such a structure, the following can be avoided: if the calculated origin position is deviated from the original position due to some reason such as poor operation, an improper position monitoring process is performed.
In the above, the manner in which the control system has the 1 st sensor and the 2 nd sensor is mentioned, but hereinafter, instead of this, the manner in which the control system has only the 1 st sensor is mentioned. For example, in the control system described above, when the at least one sensor is a1 st sensor that detects that the target device has reached the predetermined position, the encoder may store the 2 nd position information, the acquisition unit may acquire an ascent and descent of a detection signal from the 1 st sensor, the calculation unit may calculate the 1 st position information based on the ascent and descent of the detection signal from the 1 st sensor according to the movement of the target device under the predetermined drive control, and compare the 1 st position information with the 2 nd position information, and calculate a position indicated by the 2 nd position information as the origin based on a result of the comparison.
In such a configuration, the setting unit sets the origin based on the comparison result between the 1 st position information associated with the 1 st predetermined position and the 2 nd position information stored in the encoder. Since the 1 st position information is calculated by using the rising and falling of the detection signal as described above, it is not easily affected by the movement of the target device, and the position accuracy is relatively high. Therefore, the comparison result obtained by comparing the 1 st position information and the 2 nd position information can be a high-precision comparison result in accordance with the precision of the 1 st position information. As a comparison method of the two pieces of position information, for example, the position information of the origin that should be originally present is stored as the 2 nd position information, and the 1 st information calculated by the calculation unit is compared with the 2 nd position information, and if the deviation is within the allowable range, it can be determined that the position coordinates in the real object device substantially match the assumed position coordinates with the 2 nd position information as the origin. In such a case, the following can be avoided: even if the 2 nd position information is set as the origin, the position monitoring function in the real object device is adversely affected.
In the predetermined drive control in the control system, the target device may be driven at a constant speed, and in this case, the calculation unit may calculate the 1 st position information based on an intermediate point between the rising and falling of the detection signal from the 1 st sensor. In addition, information indicating a location other than this may be used as the 1 st position information.
Here, in the control system described above, the acquisition unit may be configured to: in the predetermined drive control, when the target device performs the turning-back operation in a period from the rise of the detection signal from the 1 st sensor to the passage of the detection signal from the predetermined position, the rise and fall of the detection signal from the 1 st sensor are not acquired. When such a folding operation is performed, it becomes difficult to acquire position information that is not easily affected by the movement of the target device by discontinuously outputting the rising and falling of the detection signal to be acquired in the sensor 1. Therefore, when the folding operation is performed, the process of the acquisition unit is preferably not performed.
Effects of the invention
It is possible to provide a technique capable of improving safety performance related to position monitoring of a target device that is drive-controlled by a motor with a simpler structure.
Drawings
Fig. 1 is a schematic view of fig. 1 showing a configuration of a servo system in which a servo driver is incorporated.
FIG. 2 is a functional block diagram of a servo driver of the present invention.
Fig. 3 is a flowchart of a position monitoring process performed by the servo driver of the present invention.
Fig. 4 is a flowchart of the origin setting process performed by the servo driver of the present invention.
Fig. 5A is fig. 1 showing a calculation procedure of an origin in the origin setting processing shown in fig. 4.
Fig. 5B is a diagram showing the movement of the workpiece when the origin calculating unit shown in fig. 5A is executed.
Fig. 6 is fig. 2 showing a calculation procedure of an origin in the origin setting processing shown in fig. 4.
Fig. 7 is fig. 3 showing a calculation procedure of the origin in the origin setting processing shown in fig. 4.
Detailed Description
< Application example >
An application example of the control system according to the embodiment will be described with reference to fig. 1 and 2. Fig. 1 is a schematic configuration diagram of a servo system in which a servo driver 4 is incorporated. The servo system mainly has a network 1, a motor 2, an encoder 3, a servo driver 4, a standard PLC (Programmable Logic Controller: programmable logic controller) 5 and a safety PLC 6. A servomotor is formed by a motor 2 and an encoder 3. The servo system is a system for driving the motor 2, and the motor 2 is incorporated into various mechanical devices (not shown) (for example, an arm of an industrial robot and a conveyor) as actuators of the devices. Hereinafter, the target device to be driven and controlled by the motor 2 will be referred to as a workpiece. The motor 2 is, for example, an AC motor. The encoder 3 is attached to the motor 2 to detect the operation of the motor 2. The encoder 3 generates a feedback signal indicating the detected operation of the motor 2, and transmits the feedback signal to the servo driver 4. The feedback signal includes, for example, positional information about the rotational position (angle) of the rotary shaft of the motor 2, information about the rotational speed of the rotary shaft, and the like. As for the encoder 3, a general absolute encoder may be applied.
The servo driver 4 receives an action command signal related to the action (motion) of the motor 2 from the standard PLC 5 via the network 1, and receives a feedback signal output from the encoder 3. The servo driver 4 performs servo control related to driving of the motor 2 based on an operation command signal from the standard PLC 5 and a feedback signal from the encoder 3. The servo driver 4 is connected to the safety PLC 6 via the network 1. Thus, the servo driver 4 performs various monitoring processes based on the monitoring command signal received from the safety PLC 6, and returns the result to the safety PLC 6. For example, as described later, the servo driver 4 performs a position monitoring process of the workpiece that is drive-controlled by the motor 2.
The servo driver 4 calculates a command value related to the operation of the motor 2 from the operation command signal from the standard PLC 5 and the feedback signal from the encoder 3. The servo driver 4 supplies a drive current to the motor 2 so that the operation of the motor 2 follows the command value. The supply current is supplied with ac power transmitted from the ac power source 11 to the servo driver 4. In the present embodiment, the servo driver 4 is a type of a servo driver that receives three-phase alternating current, but may be a type of a servo driver that receives single-phase alternating current.
Here, a more specific configuration of the servo driver 4 will be described. Fig. 2 is a functional block diagram of the servo driver 4. As shown in fig. 2, the servo driver 4 includes a feedback processing unit 41, a motor control unit 42, a cutting unit 43, a driving unit 44, a safety control unit 50, and a setting unit 60. The feedback processing unit 41 generates a feedback value from the feedback signal from the encoder 3. For example, when a pulse is output from the encoder 3, the feedback processing unit 41 calculates the rotational position and rotational speed of the rotation shaft of the motor 2 by counting the pulse, and generates a feedback value including a value indicating the position and the speed.
The encoder 3 is an absolute encoder, and has a circuit that doubles so as to be able to output independent pulses by scanning at the same time, and outputs a doubled feedback signal. Accordingly, the feedback processing section 41 receives the doubled feedback signals from the encoder 3, and generates doubled feedback values from these feedback signals. Then, the feedback processing unit 41 transmits the generated double feedback value to the motor control unit 42 and also to the safety control unit 50.
Next, the motor control unit 42 receives an operation command signal from the standard PLC 5 and a feedback value from the feedback processing unit 41. The motor control unit 42 generates a command value for performing position feedback control and speed feedback control based on the operation command signal and the feedback value. The feedback system used in the feedback control is a system that forms a servo loop suitable for a predetermined purpose (for example, conveyance of cargo) of a machine (conveyor or the like) in which the motor 2 is incorporated, and can be appropriately designed. These command values generated by the motor control unit 42 are then transmitted to the cutting unit 43 as drive signals.
Next, when receiving a shut-off signal from the safety control unit 50 described later, the shut-off unit 43 stops the driving unit 44 by not electrically passing a driving signal from the motor control unit 42 through the driving unit 44 described later. Thus, even if the motor control unit 42 transmits a drive signal, the output of torque by the motor 2 is stopped. On the other hand, when the shut-off signal is not input to the shut-off unit 43, the shut-off unit 43 directly passes the drive signal associated with the command value output from the motor control unit 42 through the drive unit 44.
Here, the driving unit 44 receives a driving signal from the motor control unit 42 via the cutting unit 43. The driving unit 44 includes a circuit including a semiconductor switching element such as an IGBT (Insulated Gate Bipolar Transistor: insulated gate bipolar transistor), for example, and generates a signal for turning on/off the switching element in accordance with a PWM system based on a driving signal from the motor control unit 42 and turns on/off the switching element in accordance with the signal. Thereby, ac power is supplied to the motor 2, and the motor 2 is driven in accordance with the drive signal. On the other hand, when the cutting unit 43 operates to cut off the transmission of the drive signal to the driving unit 44, the output from the driving unit 44 is fixed to be off. Thus, since the supply of electric power to the motor 2 is stopped, the output of torque from the motor 2 is stopped, and the operation of the workpiece is stopped.
As described above, the feedback processing unit 41, the motor control unit 42, the cutting unit 43, and the driving unit 44 are functional units directly related to the driving control of the motor 2. On the other hand, the safety control section 50 is a functional section that: the control state of the motor is monitored, and when the control state is in an undesirable state, the operation of the motor 2 is stopped to ensure safety against the operation. The control state to be monitored by the safety control unit 50 can be appropriately set, and in this specification, as one of the control states, the position of the workpiece to be driven and controlled by the motor 2 is used to monitor the position of the workpiece, and if the position does not fall within a predetermined monitoring range, a safety problem arises and the motor 2 needs to be stopped, and based on this consideration, the safety control unit 50 is configured to transmit a cutting signal to the cutting unit 43.
The safety control unit 50 includes a determination unit 51 and a cut instruction unit 52. The control related to the position monitoring by the safety control unit 50 is executed in accordance with the monitoring instruction from the safety PLC 6. The determination unit 51 is a functional unit that calculates the position of the workpiece (hereinafter, referred to as "workpiece position") based on a signal from the encoder 3 provided in the motor 2, and determines whether the workpiece position falls within a predetermined monitoring range. Specifically, the determining unit 51 receives the doubled feedback value from the feedback processing unit 41, and calculates the workpiece position based on the received feedback value. In this case, the origin position, which is a reference for representing the calculated workpiece position, is set by a setting unit 60 described later. The predetermined monitoring range is a range to which the workpiece position should belong in terms of safety, and can be appropriately set in consideration of the workpiece operation and the like by the motor 2. The deviation of the workpiece position from the prescribed monitoring range means that: in the driving control of the workpiece by the motor 2, there is a possibility that the driving control is not safe.
When the determination unit 51 determines that the workpiece position does not fall within the predetermined monitoring range, the cutting instruction unit 52 generates a cutting signal, and the generated cutting signal is transmitted to the cutting unit 43. The cutting unit 43 that receives the cutting signal cuts off the transmission of the driving signal from the motor control unit 42 to the driving unit 44 as described above, thereby stopping the torque output by the motor 2. The control state of the safety control unit 50 (e.g., the result of monitoring the position of the workpiece) is notified to the safety PLC 6 in the form of an answer to a monitoring command from the safety PLC 6.
Next, the setting unit 60 will be described. The setting unit 60 includes an acquisition unit 61 and a calculation unit 62. The setting unit 60 is a functional unit that performs origin setting for performing position monitoring by the safety control unit 50, and the acquisition unit 61 and the calculation unit 62 are functional units that perform processing related to the origin setting. The sensor 70 is a sensor for detecting that the workpiece has reached a predetermined position by being driven by the motor 2 within the movable range of the workpiece. In the detection signal of the sensor 70, "rise" occurs corresponding to the approach of the workpiece to the predetermined position, and "fall" occurs corresponding to the separation of the workpiece from the predetermined position. For example, in the sensor 70, when "high" is output when the workpiece is not present at the predetermined position and "low" is output when the workpiece is present at the predetermined position, the rise of the detection signal indicates a change from "high" to "low", and the fall of the detection signal indicates a change from "low" to "high". Conversely, in the sensor 70, when "low" is output when the workpiece is not present at the predetermined position and "high" is output when the workpiece is present at the predetermined position, the rise of the detection signal indicates a change from "low" to "high", and the fall of the detection signal indicates a change from "high" to "low". Then, the acquisition unit 61 acquires the rise and fall in the detection signal of the sensor 70. In the present specification, when two sensors 70 are included in the servo driver 4, reference numerals 70a and 70b are given to distinguish the respective sensors, and when one sensor is included or when it is not necessary to distinguish the respective sensors, reference numerals of 70 are given.
Next, the calculation unit 62 is a function unit that calculates the origin position for position monitoring by the safety control unit 50 using the 1 st position information related to the workpiece position calculated from the rising and falling of the detection signal of the sensor 70 acquired by the acquisition unit 61 and the 2 nd position information, which is different from the 1 st position information but related to the workpiece position in the same way. Here, the 1 st position information is calculated based on the rising and falling of the detection signal of the sensor 70, and thus, it can be said that the information indicating the position of the workpiece, which is two pieces of information related to the arrival of the workpiece at the predetermined position, that is, two pieces of information related to the approaching to and separating from the predetermined position, is considered. In other words, the 1 st position information is information determined in consideration of the approach of the workpiece to the predetermined position and the separation from the predetermined position, and is therefore said to be less susceptible to the direction from which the workpiece has reached the predetermined position. The calculation unit 62 calculates the origin for position monitoring using the 1 st position information and the 2 nd position information, and the 2 nd position information is information which is independent of the 1 st position information, although it is information related to the position of the workpiece. In this way, the 2 nd position information is position information in which the origin can be calculated by supplementing the 1 st position information, and a mode of a plurality of position information that can be used as the 2 nd position information will be described later.
Then, the origin calculated by the calculation unit 62 is used as the following origin: the origin is delivered to the safety control unit 50 by the setting unit 60, and defines a position for monitoring the position of the workpiece by the safety control unit 50. In this way, in the servo driver 4, the origin set by the setting unit 60 is less susceptible to the movement of the workpiece for origin setting (the direction of arrival toward the predetermined position), and the positional accuracy is relatively high. Therefore, even if the safety performance of the encoder 3 is relatively low, the safety performance itself based on the servo driver 4 can be improved, and therefore, the safety performance relating to the monitoring of the position of the workpiece that is drive-controlled by the motor 2 can be improved with a simpler structure.
< Structure example 1>
Here, the position monitoring process of the safety control unit 50 having the determination unit 51 and the disconnection instruction unit 52 will be described with reference to fig. 3. The position monitoring process shown in fig. 3 is repeatedly executed by an arithmetic unit (MPU, etc.) forming the safety control unit 50, for example, with a control cycle (for example, 2 msec) for generating the command value. In S101, the determination unit 51 obtains the position of the workpiece controlled and driven by the motor 2. Specifically, the determination unit 51 calculates the workpiece position using information calculated from the operation value received from the feedback processing unit 41, that is, the feedback signal from the encoder 3. At this time, the workpiece position is determined with reference to the origin set by the setting unit 60. When the process of S101 ends, the process proceeds to S102.
In S102, the determination unit 51 determines whether or not the workpiece position acquired in S101 falls within a predetermined monitoring range. The predetermined monitoring range is as described above. When the determination is affirmative in S102, the position monitoring process ends. At this time, the output of the cutting signal by the cutting instruction unit 52 is not performed. On the other hand, when the determination is negative in S102, the process proceeds to S103. In S103, the cutting instruction unit 52 generates a cutting signal, and the generated cutting signal is transmitted to the cutting unit 43. Thereby, the torque output by the motor 2 is stopped.
Next, a process (origin setting process) of setting the origin for position monitoring, which is required for realizing the above-described position monitoring process, will be described with reference to fig. 4. The origin setting process shown in fig. 4 is executed at a timing when an arithmetic unit (MPU, etc.) forming the safety control unit 50 is started, for example, by powering on the servo driver 4. In this configuration example, the servo system includes two sensors 70a and 70b. The sensors 70a and 70b are limit switches, and are disposed in correspondence with limit positions of one and the other of the movable ranges of the workpiece by the motor 2. In this configuration example, the sensor corresponding to one restriction position is the 1 st sensor 70a, and the sensor corresponding to the other restriction position is the 2 nd sensor 70b. Therefore, when the workpiece is moved from one limit position to the other limit position by the motor 2, as shown in the upper stage of fig. 5A, first, the arrival of the workpiece is detected in the detection signal SOPT a of the 1 st sensor 70a, and then, the arrival of the workpiece is detected in the detection signal SOPT2 of the 2 nd sensor 70b. At this time, the transition from "high" to "low" and the transition from "low" to "high" of the detection signal of the 1 st sensor 70a are referred to as ds11, ds12, respectively, and the transition from "high" to "low" and the transition from "low" to "high" of the detection signal of the 2 nd sensor 70b are referred to as ds21, ds22, respectively. The transition from "high" to "low" is defined as an increase in the detection signal, and the transition from "low" to "high" is defined as a decrease in the detection signal. Since the 1 st sensor 70a and the 2 nd sensor 70b serving as limit switches are sufficiently distant from each other, the on time (the period from the rise ds11 to the fall ds 12) Δt1 of the detection signal of the 1 st sensor 70a is not overlapped with the on time (the period from the rise ds21 to the fall ds 22) Δt2 of the detection signal of the 2 nd sensor 70b.
First, in S201, a predetermined drive control of the motor 2 for origin setting is performed. Specifically, the drive control of the motor 2 is performed so that the workpiece position shifts at a constant speed from one limit position to the other limit position, that is, from the 1 st sensor 70a side to the 2 nd sensor 70b side. With this drive control, as shown in the lower stage of fig. 5A, when the workpiece reaches one of the limit positions by the drive control, the rising ds11 of the detection signal SOPT1 of the 1 st sensor 70a is generated at time t11, and then the falling ds12 of the detection signal SOPT1 of the 1 st sensor 70a is generated at time t12 (t 12> t 11). Then, when the workpiece reaches the other limit position by the drive control, the rising ds21 of the detection signal SOPT of the 2 nd sensor 70b is generated at time t21, and then the falling ds22 of the detection signal SOPT2 of the 2 nd sensor 70b is generated at time t22 (t 22> t 21). In the graph shown in the lower stage of fig. 5A, the horizontal axis represents time, the vertical axis represents the position of the workpiece, and the transition of the workpiece is indicated by a line L1.
Next, in S202, the detection signal of the 1 st sensor 70a and the detection signal of the 2 nd sensor 70b are acquired during the period in which the drive control of the motor 2 is performed. Specifically, when the workpiece reaches one of the limit positions, the acquisition unit 61 acquires the rising ds11 and the falling ds12 of the detection signal SOPT a of the 1 st sensor 70 a. Then, when the workpiece moves and reaches the other limit position, the acquisition unit 61 acquires the rising ds21 and the falling ds22 of the detection signal SOPT b of the 2 nd sensor 70 b.
Here, when the rising ds11 and the falling ds12 of the detection signal SOPT a of the 1 st sensor 70a are acquired, continuity is required for the workpiece movement. When the workpiece is turned back (the movement direction is the opposite direction) after the rise ds11 is generated and until the fall ds12 is generated, the rise and fall of the detection signal of the 1 st sensor 70a are discontinuously outputted, and thus it becomes difficult to obtain the position information that is not easily affected by the movement of the workpiece. Therefore, in the origin setting process, when the workpiece performs a predetermined operation, the detection signals SOPT are not acquired from the rising ds11 and the falling ds 12. In this regard, the following cases 1 to 7 are exemplarily shown in fig. 5B. Further, the acquisition of the rising ds21 and falling ds22 of the detection signal SOPT2 of the 2 nd sensor 70b also requires the continuity of the workpiece movement.
In fig. 5B, the operations of six kinds of workpieces are illustrated corresponding to cases 1 to 6. In fig. 5B, diamond symbols indicate initial positions of the workpiece, white circle symbols indicate acquisition positions of the detection signals, and black circle symbols indicate positions from which the detection signals that were acquired were deleted. The cross symbol indicates a position where acquisition of the detection signal is not authorized, and the black triangle symbol indicates a position where acquisition of the detection signal is reserved.
In case 1, the workpiece moves from one restricting position to the other restricting position. At this time, the rising ds11 and the falling ds12 of the detection signal SOPT1 of the 1 st sensor 70a are acquired, and then the rising ds21 and the falling ds22 of the detection signal SOPT2 of the 2 nd sensor 70b are acquired.
In case 2, the workpiece moves from the other restricting position to the one restricting position, contrary to case 1. At this time, the rising ds22 and the falling ds21 of the detection signal SOPT2 of the 2 nd sensor 70b are acquired, and then the rising ds12 and the falling ds11 of the detection signal SOPT1 of the 1 st sensor 70a are acquired.
In case 3, the rising ds21 and the falling ds22 of the detection signal SOPT b of the 2 nd sensor 70b are obtained once, but then the traveling direction of the workpiece is reversed, and the workpiece is moved from the other limit position to the one limit position. At this time, the first rise ds21 and the fall ds22 of the acquired detection signal SOPT are deleted, and the rise ds22 and the fall ds21 of the subsequent detection signal SOPT2 and the rise ds12 and the fall ds11 of the subsequent detection signal SOPT1 are acquired.
In case 4, the workpiece is moved between the position corresponding to the rising ds11 and the position corresponding to the falling ds12 of the detection signal SOPT a of the 1 st sensor 70a as the initial position of the workpiece. Therefore, the acquisition of the drop ds12 of the initial detection signal SOPT1 is not authorized. The acquisition of the detection signal accompanying the subsequent work operation is substantially the same as in case 3.
In case 5, the workpiece is first moved to the other limit position side and then moved from the one limit position side toward the initial position, with the initial position being between the one limit position and the other limit position. At this time, the rising ds21 and the falling ds22 of the detection signal SOPT2 of the 2 nd sensor 70b are obtained, and then the rising ds11 and the falling ds12 of the detection signal SOPT1 of the 1 st sensor 70a are obtained.
In case 6, the workpiece is first moved to the other limit position side between the one limit position and the other limit position as the initial position of the workpiece, but after the rise ds21 of the detection signal SOPT is generated and before the fall ds22 is generated, the workpiece is turned back, and as a result, the fall ds21 is generated. In this way, when the workpiece is inverted between the transitions ds21 and ds22 of the detection signal, the acquisition of the rising ds21 and the falling ds21 is not authorized. Then, the workpiece moves to one of the limit positions, and after the rising ds12 of the detection signal SOPT is generated and before the falling ds21 is generated, the workpiece is turned back, and as a result, the falling ds12 is generated. In this way, when the workpiece is inverted between the transitions ds12 and ds11 of the detection signal, the acquisition of the rising ds12 and the falling ds12 is not authorized.
In S203, it is determined whether or not the acquisition of the rise and fall of SOPT a of the detection signal of the 1 st sensor 70a and the acquisition of the rise and fall of SOPT of the detection signal of the 2 nd sensor 70b are successful. If the determination is affirmative in S203, the flow proceeds to S204, and if the determination is negative, the origin setting process is terminated.
In S204, the 1 st position information is prepared based on the rise and fall of SOPT th detection signal of the 1 st sensor 70a, and the 2 nd position information is prepared based on the rise and fall of SOPT th detection signal of the 2 nd sensor 70 b. The preparation of the 1 st position information and the 2 nd position information will be described by taking as an example a case where the workpiece is moved as shown in case 1, that is, a case where the detection signals of the respective sensors are generated as shown in fig. 5A. In this example, considering that the workpiece is kept constant at a constant speed, the 1 st position information is set as information of a position corresponding to an intermediate point p10, the intermediate point p10 being an intermediate point of a position p11 corresponding to the ascending ds11 and a position p12 corresponding to the descending ds 12. Similarly, the 2 nd position information is information of a position corresponding to an intermediate point p20, and the intermediate point p20 is an intermediate point between a position p21 corresponding to the ascending ds21 and a position p22 corresponding to the descending ds 22. When the process of S204 ends, the process proceeds to S205.
In S205, the origin is calculated from the 1 st position information and the 2 nd position information prepared in S204. The origin is calculated by the calculation unit 62. Specifically, considering the case where the workpiece is kept constant at a constant speed, the intermediate position ps0 between the position p10 indicated by the 1 st position information and the position p20 indicated by the 2 nd position information is calculated as the origin. The origin calculated in this way is delivered to the safety control unit 50 by the setting unit 60 in the process of S206, and is set as the origin for safety monitoring.
In this way, in the origin setting process, the 1 st position information and the 2 nd position information are calculated in consideration of both the rising and falling of the detection signal, and therefore, it is possible to obtain information indicating the position of the workpiece which is less likely to be affected by which direction the workpiece reaches the predetermined position and which has relatively high accuracy. This means that the safety performance itself based on the control system can be improved even if the safety performance of the encoder 3 is relatively low. As a result, as a control system, safety performance relating to position monitoring of the workpiece driven and controlled by the motor 2 can be improved with a simpler structure.
< Modification >
In the origin setting process described above, in order to avoid a situation in which the calculated origin position is deviated from the original position due to some reason such as an operation failure and the safety control unit 50 performs an improper position monitoring process, the distance between the position related to the 1 st sensor 70a and the position related to the 2 nd sensor 70b may be monitored. Specifically, when at least one of the following conditions 1 and 2 is not satisfied, the setting unit 60 does not perform the origin setting process in S206 even if the origin is calculated in S205.
Condition 1:
The distance (p 21-p 11) between the position p11 corresponding to the rise ds11 of the detection signal SOPT a from the 1 st sensor 70a and the position p21 corresponding to the rise ds21 of the detection signal SOPT2 from the 2 nd sensor 70b is equal to or smaller than the predetermined 1 st reference distance.
Condition 2:
The distance (p 22-p 12) between the position p12 corresponding to the falling ds12 of the detection signal SOPT a from the 1 st sensor 70a and the position p22 corresponding to the rising ds22 of the detection signal SOPT2 from the 2 nd sensor 70b is equal to or smaller than the predetermined 2 nd reference distance.
< Structure example 2>
A description will be given of a2 nd configuration example of the embodiment to which the origin setting process shown in fig. 4 can be applied, with reference to fig. 6. In the present configuration example, the servo system includes two 1 st and 2 nd sensors 70a and 70b, but the 1 st sensor 70a is a photoelectric sensor and the 2 nd sensor 70b is a proximity sensor. Furthermore, the two sensors are located adjacent to each other within the movable range of the workpiece. Therefore, as shown in the upper stage of fig. 6, a part of the on time (period from the rise ds11 to the fall ds 12) Δt1 of the detection signal of the 1 st sensor 70a is overlapped with the on time (period from the rise ds21 to the fall ds 22) Δt2 of the detection signal of the 2 nd sensor 70 b.
Therefore, when the motor 2 moves the workpiece as in case 1 of fig. 5B, as shown in the upper stage of fig. 6, first, the arrival of the workpiece is detected in the detection signal SOPT a of the 1 st sensor 70a, and the rise ds11 is generated. Then, before the falling ds12 of the detection signal SOPT1, the arrival of the workpiece is detected in the detection signal SOPT of the 2 nd sensor 70b to generate the rising ds21. Then, the falling ds12 of the detection signal SOPT1, the falling ds22 of the detection signal SOPT2 are sequentially inputted. In such a configuration, when the determination is affirmative in S203 of the origin setting process, in S204 that follows, the 1 st position information is set as information of the position corresponding to the intermediate point p10 in consideration of the fact that the workpiece is kept constant at a constant speed, the intermediate point p10 being the intermediate point between the position p11 corresponding to the ascending ds11 and the position p12 corresponding to the descending ds 12. Similarly, the 2 nd position information is also information of a position corresponding to an intermediate point p20, and the intermediate point p20 is an intermediate point between a position p21 corresponding to the ascending ds21 and a position p22 corresponding to the descending ds22. In the next step S205, the intermediate position ps0 between the position p10 indicated by the 1 st position information and the position p20 indicated by the 2 nd position information is considered to be the origin, and the setting unit 60 delivers the intermediate position ps0 to the safety control unit 50 and sets the intermediate position as the origin for safety monitoring in the process of S206.
In this configuration example, continuity is required for the workpiece movement when the rising ds11 and the falling ds12 of the detection signal SOPT a of the 1 st sensor 70a are obtained and when the rising ds21 and the falling ds22 of the detection signal SOPT2 of the 2 nd sensor 70b are obtained. Therefore, as shown in fig. 5B, when the workpiece is turned back between the rising and falling of the detection signal SOPT or SOPT, the acquisition of the rising and falling related to the operation is not authorized. In addition, the monitoring of the distance between the position related to the 1 st sensor 70a and the position related to the 2 nd sensor 70b shown in the above-described modification may be applied to the present configuration example.
In this configuration example as well, since the 1 st position information and the 2 nd position information are calculated in consideration of both the rising and falling of the detection signal, it is possible to obtain information indicating the position of the workpiece which is less likely to be affected by which direction the workpiece has reached the predetermined position and which has relatively high accuracy. Therefore, as a control system, safety performance related to position monitoring of the workpiece driven and controlled by the motor 2 can be improved with a simpler structure.
< Structure example 3>
A 3 rd configuration example of the embodiment to which the origin setting process shown in fig. 4 can be applied will be described with reference to fig. 7. In this embodiment, the servo system includes a 1 st sensor 70, and the 1 st sensor 70 may be a photoelectric sensor or a proximity sensor. The encoder 3 has a memory therein, and stores information indicating the origin position (origin position information) in the memory in advance. Then, when the workpiece is moved by the motor 2 as in case 1 of fig. 5B, as shown in the upper stage of fig. 7, first, the arrival of the workpiece is detected in the detection signal SOPT1 of the 1 st sensor 70 to generate the rise ds11 thereof, and then the fall ds12 thereof is made.
In such a configuration, when the determination is affirmative in S203 of the origin setting process, in the following S204, the 1 st position information is set as information of the position corresponding to the intermediate point p10 in consideration of the fact that the workpiece is kept constant at a constant speed, the intermediate point p10 being the intermediate point between the position p11 corresponding to the ascending ds11 and the position p12 corresponding to the descending ds 12. On the other hand, regarding the 2 nd position information, the origin position information stored in the memory of the encoder 3 is set as the 2 nd position information. In fig. 7, p20 represents the origin position represented by the 2 nd position information (origin position information).
In the next step S205, the 1 st position information and the 2 nd position information prepared in S204 are compared, and the origin is calculated based on the comparison result. Specifically, when the position p10 indicated by the 1 st position information calculated from the rising ds11 and the falling ds12 of the detection signal SOPT falls within a predetermined range (within Δp1 centered on p 20) with respect to the position p20 indicated by the 2 nd position information, that is, when the deviation between p10 and p20 falls within a predetermined range with respect to p20, it can be determined that the position coordinates in the real workpiece substantially match the assumed position coordinates with respect to the origin of the 2 nd position information. Therefore, in such a case, the following can be avoided: even if the position p20 indicated by the 2 nd position information is delivered to the safety control unit 50 by the setting unit 60 and set as the origin for safety monitoring in the processing of S206, the position monitoring function in the actual workpiece is adversely affected. Since the 1 st position information is calculated by using the rising ds11 and the falling ds12 of the detection signal SOPT as described above, the position information is less susceptible to the movement of the workpiece, the position accuracy is relatively high, and the position accuracy of the origin setting can be improved.
Here, in the present configuration example, when the rising ds11 and the falling ds12 of the detection signal SOPT of the 1 st sensor 70 are acquired, continuity is required for the workpiece movement. Therefore, as shown in fig. 5B, when the workpiece is turned back between the rising and falling of the detection signal SOPT1, the rising and falling of the workpiece is not permitted to be acquired.
< Annex 1>
A control system that monitors a control state of a target device that is drive-controlled by a motor (2), the control system comprising:
A determination unit (51) that calculates the position of the target device from the signal from the encoder (3) provided in the motor (2), and determines whether or not the position of the target device falls within a predetermined monitoring range;
a cutting unit (43) that cuts off transmission of a drive signal transmitted to the driving unit (44) in order to supply a drive current from the driving unit (44) to the motor (2);
A safety control unit (50) that executes a cutting process of the drive signal via the cutting unit (43) when the determination unit (51) determines that the position of the target device does not belong to the predetermined monitoring range;
a setting unit (60) that sets an origin for the predetermined monitoring range; and
At least one sensor (70, 70a, 70 b) for detecting the arrival when the target device reaches a predetermined position by driving the target device by the motor within a movable range of the target device,
The setting unit (60) has:
An acquisition unit (61) that acquires an increase in the detection signal corresponding to the approach of the target device to the predetermined position and a decrease in the detection signal corresponding to the separation of the target device from the predetermined position, with respect to the detection signal output from the at least one sensor (70, 70a, 70 b) corresponding to the target device reaching the predetermined position when the motor (2) performs predetermined drive control on the target device; and
And a calculation unit (62) that calculates the origin using 1 st position information and 2 nd position information that are calculated from the rising and falling of the detection signal and that are related to the position of the target device, the 2 nd position information being different from the 1 st position information and being related to the position of the target device.
Description of the reference numerals
1: A network; 2: a motor; 3: an encoder; 4: a servo driver; 43: a cutting section; 44: a driving section; 50: a safety control unit; 51: a judging unit; 52: a cut-off instruction unit; 60: a setting unit; 61: an acquisition unit; 62: a calculation unit; 70. 70a, 70b: a sensor.
Claims (9)
1. A control system that monitors a control state of a target device that is drive-controlled by a motor, the control system comprising:
a determination unit that calculates a position of the target device based on a signal from an encoder included in the motor, and determines whether the position of the target device falls within a predetermined monitoring range;
A cutting unit that cuts off transmission of a drive signal transmitted to the drive unit in order to supply a drive current from the drive unit to the motor;
a safety control unit that executes a cutting process of the drive signal via the cutting unit when the determination unit determines that the position of the target device does not belong to the predetermined monitoring range;
a setting unit that sets an origin for the predetermined monitoring range; and
A plurality of sensors including a 1 st sensor that detects the arrival when the target device reaches a 1 st predetermined position and a2 nd sensor that detects the arrival when the target device reaches a2 nd predetermined position in a movable range of the target device by driving the target device by the motor,
The setting unit includes:
An acquisition unit that acquires, with respect to a detection signal output from the 1 st sensor in response to the target device reaching the 1 st predetermined position when the motor performs predetermined drive control on the target device, an increase in the detection signal in response to the target device approaching the 1 st predetermined position, a decrease in the detection signal in response to the target device moving away from the 1 st predetermined position, an increase in the detection signal in response to the target device moving closer to the 2 nd predetermined position, and a decrease in the detection signal in response to the target device moving away from the 2 nd predetermined position; and
A calculation unit that calculates 1 st position information related to a position of the object device based on rising and falling of the detection signal from the 1 st sensor, calculates 2 nd position information related to the position of the object device based on rising and falling of the detection signal from the 2 nd sensor, and calculates a predetermined candidate location between the position indicated by the 1 st position information and the position indicated by the 2 nd position information as the origin based on the movement of the object device in the predetermined drive control.
2. The control system of claim 1, wherein,
In the predetermined drive control, the target device is driven at a constant speed,
The calculation unit calculates the 1 st position information from the intermediate point between the rising and falling of the detection signal from the 1 st sensor, calculates the 2 nd position information from the intermediate point between the rising and falling of the detection signal from the 2 nd sensor, and uses the intermediate position between the position indicated by the 1 st position information and the position indicated by the 2 nd position information as the predetermined candidate location.
3. The control system according to claim 1 or 2, wherein,
The 1 st prescribed position and the 2 nd prescribed position are separated so that an on-time from the rising to the falling of the detection signal from the 1 st sensor does not overlap with an on-time from the rising to the falling of the detection signal from the 2 nd sensor.
4. The control system according to claim 1 or 2, wherein,
The 1 st prescribed position is close to or coincident with the 2 nd prescribed position so that a part or all of the on-time from the rising to the falling of the detection signal from the 1 st sensor overlaps with the on-time from the rising to the falling of the detection signal from the 2 nd sensor.
5. The control system according to claim 1 or 2, wherein,
The acquisition unit is configured to: in the predetermined drive control, when the target device performs the turning-back operation in a period from the rise of the detection signal from the 1 st sensor to the passage of the 1 st predetermined position, the rise and fall of the detection signal from the 1 st sensor are not acquired,
The acquisition unit is configured to: in the predetermined drive control, when the target device performs the turning-back operation in a period from the rise of the detection signal from the 2 nd sensor to the passage of the 2 nd predetermined position, the rise and fall of the detection signal from the 2 nd sensor are not acquired.
6. The control system according to claim 1 or 2, wherein,
The setting unit is configured to: when at least one of the condition 1 and the condition 2 is not satisfied, the setting unit does not set the origin for the predetermined monitoring range, the condition 1 is that a1 st check distance calculated from an increase in the detection signal from the 1 st sensor and an increase in the detection signal from the 2 nd sensor is equal to or smaller than a predetermined 1 st reference distance, and the condition 2 is that a2 nd check distance calculated from a decrease in the detection signal from the 1 st sensor and a decrease in the detection signal from the 2 nd sensor is equal to or smaller than a predetermined 2 nd reference distance.
7. A control system that monitors a control state of a target device that is drive-controlled by a motor, the control system comprising:
a determination unit that calculates a position of the target device based on a signal from an encoder included in the motor, and determines whether the position of the target device falls within a predetermined monitoring range;
A cutting unit that cuts off transmission of a drive signal transmitted to the drive unit in order to supply a drive current from the drive unit to the motor;
a safety control unit that executes a cutting process of the drive signal via the cutting unit when the determination unit determines that the position of the target device does not belong to the predetermined monitoring range;
a setting unit that sets an origin for the predetermined monitoring range; and
A1 st sensor that detects the arrival when the target device reaches a predetermined position by driving the target device by the motor within a movable range of the target device,
The setting unit includes:
An acquisition unit that acquires an increase in the detection signal corresponding to the object device approaching the predetermined position and a decrease in the detection signal corresponding to the object device moving away from the predetermined position, with respect to the detection signal output from the 1 st sensor corresponding to the object device reaching the predetermined position when the motor performs predetermined drive control on the object device; and
A calculation unit that calculates the origin using 1 st position information related to the position of the target device calculated based on the rising and falling of the detection signal and 2 nd position information related to the position of the target device and different from the 1 st position information,
The encoder stores the 2 nd position information,
The calculation unit calculates the 1 st position information based on the rising and falling of the detection signal from the 1 st sensor in accordance with the movement of the target device in the predetermined drive control, compares the 1 st position information with the 2 nd position information, and calculates the position indicated by the 2 nd position information as the origin based on the result of the comparison.
8. The control system of claim 7, wherein,
In the predetermined drive control, the target device is driven at a constant speed,
The calculation unit calculates the 1 st position information from the intermediate point between the rising and falling of the detection signal from the 1 st sensor.
9. The control system according to claim 7 or 8, wherein,
The acquisition unit is configured to: in the predetermined drive control, when the target device performs the turning-back operation in a period from the rise of the detection signal from the 1 st sensor to the passage of the detection signal from the predetermined position, the rise and fall of the detection signal from the 1 st sensor are not acquired.
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| JP2018222846A JP7001044B2 (en) | 2018-11-28 | 2018-11-28 | Control system |
| PCT/JP2019/043728 WO2020110653A1 (en) | 2018-11-28 | 2019-11-07 | Control system |
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| Publication number | Publication date |
|---|---|
| DE112019005932T5 (en) | 2021-08-05 |
| JP7001044B2 (en) | 2022-01-19 |
| CN112889012A (en) | 2021-06-01 |
| US20210382504A1 (en) | 2021-12-09 |
| WO2020110653A1 (en) | 2020-06-04 |
| JP2020087139A (en) | 2020-06-04 |
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